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    <script>
        // ES6 允许给函数参数赋值初始值

        // 1.形参初始值, 具有默认值的参数一般要靠后(潜规则)
        function add (a,b,c=10) {
            return a + b + c
        }
        // let result = add(1,2,3) //6
        let result = add(1,2) //13
        console.log(result) // 13
        // 2.与解构赋值结合
        // function connect (options) {
        //     let host = options.host
        //     let username = options.username
        //     let password = options.password
            // let port = options.port
            // host,username,password,port
        // }
        function connect({host='127.0.0.1',username,password,port}) {
            console.log(host,username,password,port)
        }
        connect({
            // host: 'localhost',
            username: 'root',
            password: 'root',
            port: 3306
        })
    </script>
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